This is a grant proposal concerned with problems of sudden cardiac death and the onset of myocardial infarction. The objectives include the development, application and evaluation of methods for earlier detection and therapy of individuals at risk for developing myocardial infarction and sudden death. The projects are planned to provide new information concerning the mechanisms and circumstances related to sudden cardiac death. Sudden death survivors, who are known to be at high risk for recurrence of sudden death, will be intensively studied to determine the incidence and types of arrhythmias that can be detected by monitoring and induced by exercise stress, maximum exercise stress test responses, coronary anatomy and ventricular performance by angiography, and myocardial perfusion by radionuclide techniques. The effects of drug therapy and vein bypass graft surgery in prevention of sudden and myocardial infarction will be assessed. The value of results of maximum exercise stress testing for early detection of asymptomatic individuals at risk for sudden death and/or myocardial infarction will be determined. The prognostic significance of coronary anatomy, ventricular performance and exercise stress test results with respect to development of sudden death and myocardial infarction will be evaluated. The research will be accomplished with the cooperation and collaboration of medical personnel and resources from throughout the Seattle community.